The steady increase in the traffic flow on the roads and the increase in the requirements placed upon the safety of vehicles by car drivers result in an ever increasing need to automatically detect traffic signs. Detection of traffic signs by an electronic system enables drawing a driver's attention to requirements of the respective traffic situation, and therefore enables recognizing dangers in road traffic on time and counteracting same.
For example, it is possible to detect speed limits indicated by traffic signs, or the lifting of same, by means of a system for traffic sign detection. For example, a vehicle may provide a permanent display of the current speed limit, so that a driver is informed of the speed limit even if he/she has overlooked the traffic sign dictating the speed limit. In addition, a driver may be warned, for example, by an optical or acoustic signal if he/she exceeds the maximum permissible speed (e.g. by more than a maximum permissible deviation).
Alternatively, it is also possible to detect other traffic regulations, for example regulations governing the right of way. Therefore, if the driver overlooks a traffic sign governing the right of way, which may be determined, for example, on the basis of detecting the traffic sign and further on the basis of the vehicle's speed, the driver may be warned against the dangers resulting from this. Similarly, for example, traffic signs which point out specific dangers (e.g. slippery road, steep slope, sharp bend, and the like) may be detected automatically. Again, the user may be informed or warned if he/she does not adjust his/her driving to the situation indicated by the traffic sign (for example if he/she approaches a sharp bend too fast).
Several approaches for detecting traffic signs already exist. In this context, however, there is typically the difficulty that detection of traffic signs in complex environment situations cannot occur with the very high level of safety that may be applied. In addition, conventional systems exhibit enormous problems when, for example, traffic signs are partly occluded, for example are located in a shadow area, or are dirty or damaged (e.g. bent).